A major initiative for our section is to examine the role of exposure to putative relapse triggers (such as environmental cues and stress) through the use of ecological momentary assessment (EMA). We are conducting studies in heroin/cocaineusing methadone-maintained outpatients and in obese individuals who are in a weight-maintenance program. Participants carry electronic diaries to record the base rates of exposure to putative relapse triggers as well as the presence of these triggers during relapse. We are also exploring the use of handheld electronic devices for treatment delivery in patients daily environment. Another current focus of our research derives from laboratory-animal data showing that stress-induced reinstatement of cocaine seeking and/or heroin seeking can be prevented with the alpha-adrenergic agonist clonidine, while cue-induced reinstatement of such drug seeking can be prevented with the CB1 antagonist rimonabant. We are conducting two trials of clonidine, one to evaluate its effect on response to stress and drug cues, and the second to evaluate its efficacy in relapse prevention. We are currently conducting a study in which methadone-maintained outpatients carry handheld computers throughout the day to provide real-time data on cravings for heroin and cocaine, lapses to drug use, and base rates of putative lapse precipitants. We have demonstrated the feasibility of this form of data collection in our population and are using them in the clonidine trial to determine whether its relapse- prevention effect is specific to subtypes of relapse. Finally, we are collaborating with investigators at the University of Chicago on a two-site study to investigate the time course of craving in abstinent smokers, with particular attention to the possibility of incubation, a phenomenon seen in preclinical studies, in which craving increases with duration of abstinence. Incubation of craving may help explain the long-lasting vulnerability to relapse in individuals formerly dependent on nicotine, alcohol, or illicit drugs.